1. Field of the Invention
The invention relates to a lancet device, an adjusting front mechanism for use on a lancet device, and a method of using a lancet device, In particular, the invention includes a lancet device which utilizes an adjustable tip or front. Lancet devices are used to penetrate and puncture the skin in order to allow the taking of a blood sample for testing. The device allows the user to control the depth of this penetration by a simple adjustment mechanism.
2. Discussion of Background Information
Lancet devices are commonly used to prick the skin of the user so that one or more drops of blood may be extracted for testing. Some users such as diabetics, for example, may have to test their blood sugar levels several times a day. This may be accomplished by the user using a simple needle. However, this procedure is often problematic for the user since the needle may be difficult to handle. Moreover, controlling the depth of penetration cannot be reliably accomplished without the use of a mechanical device. Additionally, many users simply cannot perform the procedure owing to either a fear of needles or because they lack a steady hand. As a result, lancet devices have been developed which allow the user to more easily and reliably perform this procedure.
Presently, most lancet devices lack convenient and flexible adjustability. Such devices are typically made adjustable by switching their tips. U.S. Pat. No. Re. 32,922 to LEVIN et al. is one such device. That is, the user must remove one tip having a set depth and replace it with another having a different set depth. This, of course, creates the problem of storing the replaceable tips, which if not properly done, may result in their misplacement, damage, contamination, or the like.
An improved device would allow the user to more easily adjust the depth of penetration and would overcome some of the disadvantages described above. Moreover, since the skin thickness can vary slightly from user to user and finger to finger, a need exists for efficiently adapting the depth of penetration. For example, an index finger may be more calloused than a middle finger, and the more calloused finger will typically have a thicker skin. By adjusting the depth of puncture so that the depth is no greater than necessary for extracting a required amount of blood, any pain experienced by the user may be minimized.
Lancets having an adjustable tip are known per se. For example, U.S. Pat. No. 4,469,110 to SLAMA discloses a mechanism which adjusts the penetration depth by rotating a threaded sleeve relative to a body. The SLAMA device is characterized as a xe2x80x9csingle bottomxe2x80x9d device which employs a threaded design which can be expensive to manufacture. Moreover, such a device may require the user to rotate the threaded sleeve up to 360 degrees and more in order to attain the proper depth setting. Further, such a threaded resign is prone to inadvertent setting changes since there is nothing but frictional engagement between the mating threads to maintain the adjustment setting.
U.S. Pat. No. 4,895,147 to BODICKY et al. functions in a similar manner to the device in SLAMA and therefore suffers from similar disadvantages.
U.S. Pat. Nos. 5,464,418 and 5,797,942 and 5,908,434 to SCHRAGA also disclose similar lancet devices and are hereby incorporated herein by reference as though set forth in full herein.
As disclosed in U.S. Pat. No. 5,908,434, the lancet device has a body portion which encloses a lancet and a lancet firing mechanism. The lancet typically has a needle extending therefrom and is caused to move towards the tip of the device by a trigger or firing mechanism. The lancet device forces the needle, by virtue of the needle being fixed thereto, out of the device by some distance or depth so that the needle can penetrate the skin of the user. The function of this firing mechanism and the lancet body design is disclosed in each of U.S. Pat. Nos. 5,797,942 and 5,908,434. These Patents are incorporated by reference herein in their entirety and are therefore only briefly discussed herein.
What is needed is a front cap or tip design which can accurately and precisely control the depth of penetration of the needle relative to the surface of the user""s skin. The front cap forms the tip portion of the lancet device. It uses an adjustment sleeve which resembles a nut and which is rotatable by the user. The nut has circumferential grooves and projections which help the user to grip it with his fingers. The nut is rotatable with respect to the front cap and/or the lancet body. Located on the inside the front cap is disposed a stop cap which is moveable in at least two directions. The stop cap can move forwards and backwards in the direction of the movement of the lancet and needle. Moreover, the stop cap can also rotate.
Thus, while advances have been made, there is a continuing need for a lancet device which provides for convenient and reliable adjustment of penetration depth.
According to one aspect of the invention there is provided a tip for a lancet device, which includes a front assembly comprising a side wall portion, a skin-engaging portion at least partially defining a plane beyond which a lancet needle may extend, and a lancet stop element, a slot disposed in one of the sidewall portion and the lancet stop element, and at least one following element extending into the slot, wherein the lancet stop element is moveable towards and away from the plane in response to movement of the at least one following element. The tip may include at least one actuator for engaging the at least one following element. The actuator may be a rotatable annular member for engaging the at least one following element. The at least one following element may be fixed to the stop member. Alternatively, the at least one following element may be fixed to the annular member. The slot may be disposed on the sidewall portion. The slot may be a camming slot. The slot may be both disposed on the stop member and may be a camming slot.
The tip may also include an outer generally annular rotatable member. The at least one following element may be fixed to the generally annular rotatable member. The generally annular rotatable member may have a slot. The slot on the generally annular rotatable member may be a camming slot. The at least one following element may be fixed to the stop member.
The tip may include at least one tooth disposed on one of the stop member and the front assembly. The front assembly may include an internal spline having a plurality of teeth for engaging the at least one tooth disposed on the stop member. The tip may have at least two ratchet teeth being disposed on the stop member approximately 180 degrees apart from one another. The stop member may include a first section which includes at least one ratchet tooth and a second section which includes a camming lug, the first section being partially separated from the second section by at least one separating slot. The first section and the second section may be partially separated by at least two separating slots such that the separating slots define at least two connecting walls. The second section may further include a deflecting wall for connecting the camming lug to a cylindrical wall of the stop cap. The second section may include a circumferential separating slot for separating a portion of the deflecting wall from the cylindrical wall of the stop member such that the deflecting wall is connected to the cylindrical wall by a connecting wall. The connecting wall allows the deflecting wall to deflect inward towards a center axis of the stop member. The stop member may be moveably retained within the front assembly such that it can rotate and move axially with respect to the front assembly. The stop member may be moveable towards and away from the plane such that at least one ratchet tooth maintains engagement with an internal spline disposed on an internal surface of the front assembly throughout this movement.
The tip may provide that the at least one following element is guided within the slot when the stop member is moved axially or rotated. The front assembly may include a bearing surface disposed between at least two shoulders, and wherein an annular member is rotatably disposed on the bearing surface and is retained from axial movement by at least one shoulder. The front assembly may further include engaging lugs which cooperate with engaging grooves on a lancet body and a manual lancet release button for separating the lancet from the lancet body. The lancet stop element may include a opening for allowing the needle to project therethrough.
The tip may further include a rotatable nut disposed on the front assembly which includes one of a plurality of projections and grooves disposed on an outer surface. The nut may include indicating marks and the front cap may further comprise a reference mark. The nut may also include a distal wall which includes an opening for allowing the needle to project therethrough.
According to still another aspect of the invention, there is provided a lancet device, which includes a lancet body including a lancet firing mechanism which is at least partially enclosed within a lancet body shell, a front assembly including a side wall portion, a skin-engaging portion at least partially defining a plane beyond which a lancet needle may extend, and a lancet stop element, a slot disposed in one of the sidewall portion, the lancet stop element, and the outer generally annular member, and at least one following element extending into the slot, wherein the lancet stop element is moveable towards and away from the plane in response to movement of the at least one following element.
The invention also provides for a front cap mechanism for a lancet device wherein the front cap mechanism includes a proximal end for attaching to the lancet device and a distal end for allowing a needle to project therefrom, the lancet having a surface from which the needle projects, the mechanism including a front cap having a distal opening adapted to allow the needle to project therethrough, a nut rotatably disposed on an outer surface of the front cap, a stop cap disposed within the front cap and adapted to allow the needle to project therethrough, the stop cap including a lancet stop surface and an opening, wherein the lancet stop surface is adapted to allow the needle to project through the opening and is adapted to prevent further movement of the lancet when the lancet surface contacts the lancet stop surface.
The mechanism may provide that the stop cap further includes at least one ratchet tooth and wherein the front cap further comprises an internal spline having a plurality of teeth for engaging the at least one ratchet tooth. The at least one ratchet tooth may be at least two ratchet teeth disposed approximately 180 degrees apart from one another. The stop cap may include a first section which includes at least one ratchet tooth and a second section which includes at least one camming lug, the first section being partially separated from the section by at least one separating slot. The first section and the section may be partially separated by at least two separating slots such that the separating slots define at least two connecting walls. The second section may include a deflecting wall for connecting the camming lug to a cylindrical wall of the stop cap. The camming lug may be guided within the circumferential camming slot when the stop cap is moved axially or rotated and wherein the camming lug engages a recess formed on the nut. The second section may also include a circumferential separating slot for separating a portion of the deflecting wall from the cylindrical wall of the stop cap such that the deflecting wall is connected to the cylindrical wall by a connecting wall. The stop cap may be moveably retained within the front cap such that it can rotate and move axially with respect to the front cap. The rotation of the nut in one direction may cause movement of the lancet stop surface towards the distal end and wherein rotation of the nut in the opposite direction may cause movement of the lancet stop surface away from the distal end.
According to another aspect of the invention, there is provided a method of puncturing a surface of skin using a lancet device which includes a lancet firing mechanism and a tip for a lancet device comprising a front assembly comprising a side wall portion, a skin-engaging portion at least partially defining a plane beyond which a lancet needle may extend, and a lancet stop element, a slot disposed in one of the sidewall portion and the lancet stop element, and at least one following element extending into the slot, wherein the lancet stop element is moveable towards and away from the plane in response to movement of the at least one following element, the method comprising adjusting a set depth of penetration of the needle by moving the at least one following element to a set position, disposing the distal end of the lancet device against a surface of skin, and triggering the firing mechanism to cause the needle to penetrate the surface of the skin to the set depth, wherein the puncture allows a sample of blood to be taken. The sample may comprise at least one drop of blood which flows up to the surface of the skin.
The invention also provides for a method of puncturing a surface of skin using a lancet device comprising a lancet body comprising a lancet firing mechanism which is at least partially enclosed within a lancet body shell, a front assembly comprising a side wall portion, a skin-engaging portion at least partially defining a plane beyond which a lancet needle may extend, and a lancet stop element, a slot disposed in one of the sidewall portion, the lancet stop element, and the outer generally annular member, and at least one following clement extending into the slot, wherein the lancet stop element is moveable towards and away from the plane in response to movement of the at least one following element, the method comprising adjusting a set depth of penetration of the needle by moving the at least one following element to a set position, disposing the distal end of the lancet device against a surface of skin, and triggering the firing mechanism to cause the needle to penetrate the surface of the skin to the set depth, wherein the puncture allows a blood sample to be taken. The sample may comprise at least one drop of blood which flows up to the surface of the skin.
The invention therefore provides for a lancet device and a method of using the device to extract one or more drops of blood for testing. The invention also provides a front mechanism which may be in the form of a cap and which is adaptable to be used on conventional lancet devices for facilitating precise needle depth control. Moreover, the invention provides such a device which may be a hand held device which is small enough to be placed in a pocket or purse. It has a body portion and a front cap or tip portion and functions in a manner similar to the devices disclosed in U.S. Pat. No. 5,908,434 and U.S. Pat. No. 5,797,942, each issued to SCHRAGA, the disclosure of each being incorporated by reference herein in their entirety. Both these Patents were issued to this inventor.
The invention provides for a front mechanism having an adjustment mechanism. This front mechanism may be utilized on many conventional lancet devices, and in particular, may be used on the above listed devices. Further, the invention provides for a new type of lancet which utilizes this adjustment front cap mechanism. In one embodiment, the front assembly or front mechanism is in the form of a cap.
The stop cap also has a camming lug which travels in a camming slot formed in a side wall of the front cap. The lug projects through the camming slot and further into a recess formed on an inside surface of the nut. In operation, this design allows the stop cap to rotate as well as move forwards and backwards, based upon rotational movement of the nut. The camming slot in the front cap is angled in such a way to allow the stop cap to be precisely positioned within the front cap. The stop cap functions, as its name suggests, as a stop for the lancet. That is, it acts to stop the movement of the lancet after it is fired in the direction of the tip. For this purpose, the stop cap has a stop surface which prevents the lancet from moving any further past a set point. Moreover, the stop cap includes a through hole which allows the needle to protrude therethrough. As a result of the needle being fixed to the lancet, the stop cap also prevents the needle""s movement past a set point.
The device functions as follows: a user rotates the nut in either a clockwise or counterclockwise direction to set or adjust the device to a certain set needle depth. This is facilitated by indicating marks formed on the nut with respect to a reference mark formed on the from cap in the form of a reference arrow. The rotation of the nut causes movement of the stop cap to a set position for prevention further movement of the lancet and needle. At this point, the user places the device with the front cap positioned against the skin. Upon activation of the trigger mechanism, the lancet and needle are caused to move towards the skin. However, the lancet and needle will not be allowed to travel past a stop point determined by the stop cap. As a result, the needle protrudes into the skin only by the desired maximum amount. That is the needle can penetrate only up to the point where the lancet contacts the stop surface. The needle penetrates and is retracted very quickly owing the speed of the spring activated plunger and firing mechanism which causes the lancet to move. At this point the user withdraws the device from the skin and stores it for later use. A drop of blood should then flow up through the puncture in the skin which can be tested.
However, should an insufficient amount of blood not surface from the puncture, the device can be re-adjusted to allow the needle to penetrate still a little further into the skin. To do so, the user merely rotates the nut in the required direction to the next indicating mark. This will in turn, cause the stop cap to move closer toward the user""s skin. The lancet device can then be rearmed and triggered, and once released will allow the needle to penetrate a little further into the skin. Of course, if an excessive amount of blood flows up or if an excessive amount of pain is experienced owing to the needle penetrating too much, then the nut can be rotated in the opposite direction to reduce the depth of needle penetration.
In one particular embodiment of the device, the nut is located on the front cap and sits back some distance from a distal surface. The distal surface being a surface which contacts the skin of the user and through which the needle projects. One advantage of this embodiment is that the nut may be easier to fabricate.
In another embodiment of the device, the nut itself includes the distal surface with the corresponding distal opening. One advantage of this embodiment is that the nut has a longer axial length which can be easier to grip. Another advantage is that the front cap may be easier to fabricate owing to its cylindrical shape having both ends open.
The invention thus provides for a front cap adjusting mechanism which can be adapted to fit on conventional lancet devices for facilitating precise needle penetration. Moreover, the invention provides for a lancet which uses the front cap. Finally, the invention provides for a method of using the device to extract blood for testing.
As explained above in connection with the device, the method allows the user to extract one of more drops of blood more efficiently, precisely, consistently, and with less discomfort to the user.